Trying to align an old Lathe

[goldstar31]

Hi Jon
Well things on the lathe itself seem in order. The next thing to find out is whether it will cut metal Accurately. In other words , dialling in a thous a a thous and. getting the intended 2 thous of mrtal removed.

I think that I've prattled about finer cuts in the recent past -- but you've done well so far

Cheers

Norman

 

[BaronJ]

Hi Guys,

Agreed ! There isn't too much that you can do about bed twist on an ML4. In theory as long as the lathe hasn't been abused or damaged, the bed should be as straight as it was when it left the factory. Any adjustment is now down to shims. But based on your gauge readings it is pretty good anyway. Making sure that the tailstock is properly aligned is important particularly if you want to do any work between centers.

 

[goldstar31]

Am I havuing a 'Senior Monent' but isn't the ML4 is a cantilever lathe?.

I Was answering a question elsewhere about an ancient na bout a Wizard/Lane lathe from County Durham here- I had a cantilever Enox which was similar. It was from the late relative of Watts the Steam kettle guy. This guy was into flash steam but was an engineer first then became a doctor. His wife - another doctor brought my wife into the world as her first baby.

So bolting down doesn't mean a lot

 

[JCSteam]

Hi Jon
Well things on the lathe itself seem in order. The next thing to find out is whether it will cut metal Accurately. In other words , dialling in a thous a a thous and. getting the intended 2 thous of metal removed.

I think that I've prattled about finer cuts in the recent past -- but you've done well so far

Cheers

Norman

Norman, Itll never do that because of the cross slide 12TPI leadscrew, which means it traverses 0.00104" for every notch on the dial. 80 dial indicators. I think to be more accurate it has to be 83 notches or something, but i would like to know what went through the head of the designer that thought this was acceptable. Knowing about that error does help though as it can be taken in to account, but the new cross slide has much less backlash than the previous one. I think to about half in fact.
Also yes it is a cantilever bed, i have it raised on jacking points, so the bed can be twisted ever so slightly, (and i mean slightly) which helps bring it into line.
Jon

 

[goldstar31]

Nah! Young Jon

I. reckom that the Leadscrew is EIGHT whilst the Feedscrews are 12 giving 64.5 revolutions per full turn.

I arsed about with an early ML that once made Northumbrian small pipes. Long time ago.

 

[JCSteam]

Hi Guys,

Agreed ! There isn't too much that you can do about bed twist on an ML4. In theory as long as the lathe hasn't been abused or damaged, the bed should be as straight as it was when it left the factory. Any adjustment is now down to shims. But based on your gauge readings it is pretty good anyway. Making sure that the tailstock is properly aligned is important particularly if you want to do any work between centers.

I set my lathe up on four jacking points which effectively gets rid of if the surface the lathe is bolted to isn't level, (a kitchen workbench unit and 38mm chipboard top). I have done these measurements with just the headstock end of the bolts done up. The tail stock ones arent adjusted at all yet. The jacking points are four M8 studs, nuts and repair washers, to allow the bed to be manipulated. I have not noticed any issues with this and seems to be good at adjusting twist even in the cantilever bed.

Need to paint the tailstock first, before putting it on the lathe, I know there is movement in the bore, but with the barrel locked up this is minimised, a gentle nip if im drill helps too. Its centre the tailstock with the test bar, then the moment of truth an 18" long 1" shaft from work, will be put between centres and checked to see how true it remains.

Regards
Jon

 

[JCSteam]

Nah! Young Jon

I. reckom that the Leadscrew is EIGHT whilst the Feedscrews are 12 giving 64.5 revolutions per full turn.

I arsed about with an early ML that once made Northumbrian small pipes. Long time ago.

Its early and maths was never my strong point but! Yes leadscrew is 8TPI and feed screws are 12TPI.

1" travel / 80 divisions of the dial / 12TPI feedscrews = 0.0010416"r for every indication on the dial. Myford stated this in their catalogue and took me a while to work out how they derived that number. But all divided together meant that the Myford lathe had a crap accuracy over long parts such as shell casings, which is probably why myford got told to make the drummond lathe instead which has 10TPI feedscrews for the war effort as they were more precise than myford.
Jon

 

[BaronJ]

Hi Guys,

Actually it doesn't matter at all. If you angle the top slide you can easily take a fraction of a thou off your work without even moving the cross slide. I forget what the angle is to set it to, something like 5.5 degrees, then each division becomes a tenth.

About the only time I bother about fractions of a thou is bearing fits, even then its easier to use fine emery cloth and oil.

 

[fcheslop]

A wee bit of history. When the ML4 was new very few toy makers would own micrometers and would simply use calipers and split the line on a rule. So the fit was either good or like an arse in a pot. My first lathe didnt have graduations just one line to count the turns
To get round the wacky system they used simply fit a clock to the cross slide and read from it instead if the original dial or mount on of those mickey mouse digi calipers to the slide saves all the head scratching
Nice to see it coming back together its about time it made a toy or three
What dia was the shaft as you may need to use a travelling steady or on of these I copied from a well known maker
I had to make 20 odd feet for an automata. Keep the sound down as the poor machine was in top speed

cheers

 

[Dusty3v0]

Wouldn't the areas on the chuck where the jaws ride, being softer, wear rather than the hardened jaws.

Indeed. The four jaw was used, but id still hope to get somewhere close using just the 3 jaw. All chucks were tried, like i said with the reversed jaws where i had them as the theory was if they were worn then the other jaws would not have as much use...

Jon

 

[goldstar31]

Wouldn't the areas on the chuck where the jaws ride, being softer, wear rather than the hardened jaws.

I think that the jaws of the independent chuck and the SC Chusck ate both quite hard. For some with a rather more sketchy workshop, I'd rate then as bloody hard.

The only time that you will get soft jaws is -----to get soft jaws

 

[BaronJ]

A wee bit of history. When the ML4 was new very few toy makers would own micrometers and would simply use calipers and split the line on a rule. So the fit was either good or like an arse in a pot. My first lathe didnt have graduations just one line to count the turns
To get round the wacky system they used simply fit a clock to the cross slide and read from it instead if the original dial or mount on of those mickey mouse digi calipers to the slide saves all the head scratching
Nice to see it coming back together its about time it made a toy or three
What dia was the shaft as you may need to use a travelling steady or on of these I copied from a well known maker
I had to make 20 odd feet for an automata. Keep the sound down as the poor machine was in top speed

cheers

I've used a similar technique for making long lengths of threaded bar. It works very well for smaller diameters and finer threads like M6, 3/16 W and BA. Smallest I've done has been 8BA and the biggest M6. Though because of the difficulty I've experienced in grinding threading bits, I've since gone onto carbide inserts for threading. Saves a lot of frustration.